Sunk in the depths of the Earth's mantle, thousands of km below the surface, two enormous and strange blobs of rock much denser than the rest have been challenging scientists' ability to understand for decades. These are two giant masses, two "superfeathers" that are known, by their acronym in English, as LLSVP, 'Large low-shear-velocity provinces'. One of them is buried just below Africa, and the other lies under the Pacific Ocean.
The size of these rock masses is such that both are capable of generating their own disturbances in the magnetosphere, including the great phenomenon that currently weakens the Earth's magnetic field and is known... See more